Turns out the one spreading the rumors was Hashimoto, who did so at the behest of Sakayanagi. Shortly thereafter, Sakayanagi appears before Class C and she informs them she has evidence regarding the rumors about Ichinose.
The "best by" date on the can she gave me
تاريخ الصلاحيّة على علبتها
Das Haltbarkeitsdatum
La fecha de caducidad de la lata
La fecha de caducidad de la lata
Sa date de péremption
Aveva una data di scadenza
A data de validade da lata que ela me deu
Срок годности у неё
истекает на год раньше,